RANGER-5554: Refactor Ranger Admin bootstrap to use runtime XML config only

[kumaab]

What changes were proposed in this pull request?

Refactors the ranger-admin Docker bootstrap flow to use runtime XML configuration and environment variables instead of the legacy installer path (setup.sh, install.properties, and related setup scripts).

Key changes:

• Switches admin container startup to runtime-driven config using ranger-admin-site.xml
• Adds Python helpers for DB setup, XML config handling, password bootstrap, and logging
  • Introduces logging with config to be used for logging across python scripts. All log statements use logger now.
  • Passwords are now driven from env variables in docker compose, eliminates hardcoded passwords in .xml file.
  • Authn and user/password validations/resets are now handled via apache-ranger python client.
  • Helper methods are grouped into respective classes RangerAdminXmlConfig and UserPasswordBootstrap for maintainability and readability.
• Removes dependency on ranger-admin-install-postgres.properties
• Updates ranger.sh to prepare runtime config, wait for DB readiness, seed initial passwords, and bootstrap services
• Updates Docker build/compose to use mounted XML config assets and the new helper scripts
• Breaking change: breaks existing docker installation compatibility with other DB flavors.

How was this patch tested?

• built the ranger-admin image
• ranger-admin starts with mounted XML config and env-based passwords
• Verified Ranger Admin comes up successfully and UI login works, no errors seen in catalina.out
• Verified default services are created
• Verified fresh install picks up configured admin/usersync/tagsync passwords

Pending

• Integration with Solr